Say I do an add instruction.
Then, the accumulator becomes negative.
What does that mean? Is that invalid?
Context-:
I am studying symbolic microprogram from Morris Mano's COA book.
On page 229 of his book, he mentions an interesting and confusing thing.
BRANCH instxn should cause a branch to effective address if AC<0(AC<0 when S=1, i know this).
this should cause a branch to effective address(address of operand i guess, but which operands?)
and if S=0, no branch occurs
Reference Figures-:
Then, the accumulator becomes negative.
What does that mean? Is that invalid?
Context-:
I am studying symbolic microprogram from Morris Mano's COA book.
On page 229 of his book, he mentions an interesting and confusing thing.
BRANCH instxn should cause a branch to effective address if AC<0(AC<0 when S=1, i know this).
this should cause a branch to effective address(address of operand i guess, but which operands?)
and if S=0, no branch occurs
Reference Figures-: